Handler robots may be used to transfer payloads between stations, e.g., vacuum robots may be used in semiconductor manufacturing to transfer a wafer between load locks and the wafer orienter. Fixtures may be used at the stations to center the end effector, or payload pick over the stations, so as to teach the robots the station positions. In order to minimize misplacement of the payload at its destination station, the taught positions may be at the center of the locations of the stations, or may be displaced in the same direction and magnitude relative to the station locations.
Generally, the robots may be taught by means of an operator manually placing the end effector over the target fixture at the stations and recording the position. Thus, the quality of the alignment may be a function of the operator's skill in placing the end effector over the target. Alignment errors due to human variability may result in misplacement of the payloads that may cause damage to the payloads and/or the handling equipment.